I housed an anarduino (arduino compatible with integrated rfm-69 radio) into a bg-e8 battery grip for my t3i. The anarduino just happens to fit perfectly in the recessed area where you would store your battery cover inside the grip:
This is so freakin awesome! This is the arduino board that I use to start and stop all our dslr’s and external audio wirelessly on a multicam shoot.
You can order this banger from: http://www.anarduino.com/miniwireless/
For now I have only connected the shutter and half shutter functions to the arduino, I could also control the shutter speed dial from arduino, which would be useful for holy grail timelapse sequences.
Wire some outputs to the button terminals in the grip and enable “record on shutter half-press” in magic lantern
If you’re gonna attempt this you should probably know how to map pins and stuff. There’s plenty of info so i won’t repeat it here, the important thing is the buttons on the grip just pull logic low so The loop looks like this:
pinMode (shutter,OUTPUT);
digitalWrite(shutter,LOW);
delay(10);
pinMode (shutter,INPUT);
digitalWrite(shutter,HIGH);